Condensing steam-engine.



J. DAVIDSON.

GONDENSING STEAM ENGINE.

APPLICATION- FILED JUNE 12, 1011,

Patented Feb. 20, 1912 gines and has for its UNITED strATEs PA ENT, cur os.

aonn DAVIDSON, or rnunnn'ron, enema.

. CONDENSING STEAM ENGINE.

To all whom it may concern:

Be it known that 1, JOHN DAVIDSON,.21 subject- .of the 'King of Great Britain. residing at Pendleton, inthe county of Lancaster, Kingdom of Great Britain, have invented certain new and useful Improvements in and Connected with Condensing Steam-Engines, of which the following is'a specification, reference being had therein to the accompanying drawing.

My inventionrelates to improvements in and connected with condensing steam enobject to provide such engines with a valve which will not only drain the water in the cylinderin the ordinary way but also relieves excessive. pressure in the cylinderdue to compression should 'the vacuum fail. and the engine have ,to run non-condensing. I In practiceit has been found that in the case ofen'gines working with a high degree of compression, that is to say, .engines-in which the exhaust valve closes some consid erable time before the piston reaches the (end of the stroke and particularly in the case of engines where the exhaust takes place through the ports which are uncovered by the pistonnear the end of its stroke and consequently closed very early on its return stroke, very-high compression pressures are reached should the condenser fail and the engine have to exhaustinto the atmosphere unless relief valves of ample size are fitted.

The valve constructed in accordance with my invention works'as ans-ordinary pressure relief valve so lon -as the vacuum is maintained but immediately it fails and the com-- pression pressure in the cylinder slightly exceeds the initial steam pressure it will open wide.

It also dispenses with the ordinary arrangement of drainvalves, as it will open freely with a few pounds pressure when starting the engine.

I attain theseobjectsby the means illustrated in annexed drawing, Figure 1 showing the same employed in, and Fig. 2 attaclied to the cylinder end casting of a condensing steam engine, .both figures being vertical sections.

Similar letters refer -to similar parts throughout the several views.

In carrying out ferring to the figures generally, I employ a valve a in the cylinder end casting b, Fig. 1,

or in a casting b Fig. 2, suitably connected Specification of Letters Patent. Application filed .Tune 12, 1911.

valve by itself excess of the boiler pressure.

my' invention and re- Serial No. 632,740.

with the'cylinder end casting I) and the exhaust pipe or condenser (not shown), which acts as an ordinary drain, re-. lief or safety valve and is held onto its seat 0 by a spring d 'of a pressure somewhat in \Vh'en this valve opens the condensed water can pass from the cylinder 6 through'a port -f and pipe 7 to the. exhaust pipe or condenser of the engine. I

In alinement' with the drain valve a I employ a second valve h bearing against the drain valve spring (Z and held toits seat i by a spring'k much weaker than the drain valve spring (I, say only strong enough to close itsvalve with a pressure of say 3 or 4 pounds per square inch. Under working conditions, the outer side of the second valve h isopen to the steam chest or steam inlet pipe of the engine and consequently being of considerably larger diameter than the drain valve a, it will be held to its seat 2' with a greater pressure than that required and exerted by the drain valve spring (Z and Patented Feb. 20,1912.

hence the steam pressure will keep both .valves (1 and h to their seats.

At aright angle with. the two valves (1 and h I employ-an ordinary screw down valve Z for starting purposes. ll hen this valve is shut, steam from the steam chest is cut oil from the chamber in of the second valve h p and the latter will only be pressed toward its seat by its spring it: which will be easily overcome by the drain water spring (l and moving outward -will relieve the drain valve of a great amount of pressure and allow it to open freely to permit the condensed water or the like to pass out thus acting as an efficient drain valve 'of large area.

On the pipe 9 connected with the exhaust pipe or condenser (not shown) and. the port 7 leading to the drain valve o,'I employ in close proximity to the cylinder e a valve (not shown) which closes automatically with the automatic atmospheric exhaust valve and opens immediately the vacuum is made, or a hand operated valve may be used" in lieu thereof.

As soon as the compression pressure overcomes the pressure of the drain valve spring (Z, the drain valve a will open and perm-it the port f in connection therewith to fill with steam at high pressure which then acts upon the interior of the second valve h and brings the same almost in equilibrium. Any fur ther 'pressurein the cylinder will theneasily open the dram valve a and with it the. secpressure behind it slightly ,exceeds the pres,

sure in the steam chest or steam-pipe.

When the condenser is started again the valve on the pipe 9 is again opened by the closing. of the saidautomatic atmospheric exhaust valveor by other suitable means and the interior of the second valve it being relieved from pressure, it will be held firmly to its seat by the outside'pressure and the drain valve a will act again as an ordinary drain valve.

I claim:

1. In a condensing steam engine, a cylinder end having an outlet port communicating with the exhaust pipe, two spring in fiuencedva'lves of varying diameter in alinement with each other andt-he said port, the

smaller of the said valves being adapted to cstablish'and cut off communication betvgeen the cylinder and the exhaust pipe and; the

larger valve between the cylinder and the steam chest of the engine and normally held to its seat by .the pressure of live steam from the steam chest and by its spring when the live steam is cut off and the smaller valve 'opens'to drain the cylinder, all combined substantially as and for the purpose speci '2. In a condensing steam engine, a cylinder end having an outlet port communicating with the exhaust pipe, two valves of varying diameter in alinement with each other and the said port, a chamber in connection with the larger of the said valves communicating withthe steam chest and springs pressing the said valves to their seats, the smaller of: the said valves being adapted to establish and'cut ofi communication between the cylinder and the exhaust pipe and the larger valve between the cylinder and steam chest and normally held to its I seat by the pressure of live steam passing from the steam chest into the said chamber and by it spring when the live steam is cut oil and'the smallervalve opens to drain the cylinder, all combined substantially as and for the purpose specified.

' .3. In a condensing. steam'engme, a cylinder end having an outlet port communicating with the engine exhaust pipe, two spring influenced valves of varying diameters in alinement with each other and the said port,

the smaller of the said valves being adapted to establish and cut ca communication between the eylinder and the exhaust pipe and the larger valve between the cylinder and the larger of the'said valves communicat ing with the steam. chest, the said larger valvebeing normally ,held to its seat by the pressure .of' live steam passing from the steam chest into the said chamber and by its spring when the live steam is out off and the smallervalve opens to drain the cylinder, and a screw-down valve between the said chamberand the steam chest, all

combined substantially as and for the purpose set forth.- v

In testimony whereof I have aflixed my signature in presence of two. witnesses.

I JOHN DAVIDSON.

', Witnesses:

FERDINAND B. BOSSHARDT, STANLEY E. BRAMALL.

'steam chest, a chamber. in connection with 

